There might
be errors encountered when issuing SQL statements in a routine such as a
procedure. In SQL Server 2005 and beyond, you can programmatically handle them
using TRY and CATCH. The TRY block is where you put SQL statements you want to
execute. The CATCH block is where control is transferred in case of error.
You can call
different functions in the CATCH block to find out what went wrong, and where.
Here is a list of those functions:
·
ERROR_NUMBER()
·
ERROR_MESSAGE()
·
ERROR_SEVERITY()
·
ERROR_LINE()
·
ERROR_PROCEDURE()
·
ERROR_STATE()
To indicate
an error occurred in code, you used to call the RAISEERROR() function. You pass
it the error message, severity, and state. This would not terminate the batch
you are in. In SQL Server 2012 and beyond, you could instead do a THROW. You
give it the error number, message, and state. Note that these values are not
enclosed in parentheses for a THROW. The severity for a throw is always 16.
THROW terminates the batch. The statement directly before a THROW must end in a
semicolon.
There is a special version of THROW that has no
parameters/values. It can only be issued in the CATCH block. It will
effectively re-raise the error to the caller.
